maybe they think you got a new carpet and they don't want to get mud on it?
Cover the entire room with the runners. Now they have no choice. You've got them this time!!
It’s probably because it’s an unusual texture. Give it time and they may get used to it. They could end up avoiding it forever though. I’d recommend trying a reward based system to train them to use it. Of course, if they’re going in and out quite a bit that may prove inefficient.
I bought one of those blackhole litter mats for my cat so it would hopefully collect most of it. Extra big one at that. That punk cat decides, nope, let's just long jump over it spraying more litter everywhere
How to take care of carpeting.
Step one: throw it in the trash